[logback-user] Custom MDC Implementations?

[Paul Galbraith]

On 2024-04-17 8:51 a.m., Ceki Gulcu via logback-user wrote:
> On 4/16/2024 3:59 PM, Paul Galbraith via logback-user wrote:
>> Is it possible to write your own custom MDC implementation (similar to
>> log4j's ContextDataProvider) so that logback can get context details
>> from something other than threadlocal storage?
>
> Hi Paul,
>
> This is a recurrent request and in more recent versions of logback you
> may override the MDC implementation.
>
> To do this, you need
>
> 1) to set the custom mdcAppender in your own implementation of
> SLF4JServiceProvider
>
> and
>
> 2) by calling the setMdcAdapter() method of the loggerContext instance
> currently in use. Calling LoggerFactory.getILoggerFactory will return
> this instance. You probably have a handle on the loggerContext in your
> own implementation of SLF4JServiceProvider as mentioned in the previous
> point.
>
> An alternative under consideration, but not yet implemented, is to
> provide an extension point in SLF4J's mdcAdapter interface itself.
>
> There is a request in the SLF4J project (on github) where this is being
> discussed. You are welcome to add your voice. Here is the link
>
> https://github.com/qos-ch/slf4j/issues/399
>
> Let us know how it goes,
>
Thanks Ceki, in this issue #399 it sounds like proposal #2 is in line 
with the approach that log4j has taken with it's ContextDataProvider 
interface which can be implemented and integrated via service discovery. 
I think this (proposal #2) would solve my problem nicely.  I am trying 
to find a way to log scoped context from reactive frameworks like vert.x 
and Project Reactor where, similarly, request processing context is not 
at all framed by a time window on a single thread.  I'm also not looking 
for any help from logback in identifying and propagating context, I just 
want a hook where I can do this myself.  Probably context 
implementations for vert.x and Project Reactor could live nicely in a 
community extension repo of some sort.

In the meantime I'll take a look at implementing SLF4JServiceProvider.  
Thanks for pointing me in the right direction.

Paul